Resonant Scattering between Dark Matter and Baryons: Revised Direct Detection and CMB Limits
Xingchen Xu, Glennys R. Farrar
备注：
31+10 pages,15+3 figures. v2 adds some citations and additional analyses: (1) repulsive as well as attractive interaction, (2) separate analysis of CMB and CMB+Ly-alpha limits & non-trivial role of DM-He scattering relative to Born case, (3) Milky Way gas clouds and Milky Way satellites, (4) velocity dependence near resonances (& approximate analytic expression), (4) dependence on mediator mass
Traditional dark matter models, eg. WIMPs, assume dark matter is weakly coupled to the standard model so that elastic scattering between dark matter and baryons can be described perturbatively by Born approximation. Most direct detection experiments are analyzed according to that assumption. We show that when the fundamental DM-baryon interaction is attractive, dark matter-nucleus scattering is non-perturbative in much of the relevant parameter range. The cross section exhibits rich resonant behavior with a highly non-trivial dependence on atomic mass; furthermore, the extended rather than point-like nature of nuclei significantly impacts the cross sections. The repulsive case also requires full numerical calculation. These non-perturbative effects change existing constraints.
Near a resonance value of the parameters, the cross section has non-trivial velocity dependence rather than the usual $σ\sim v^0$; we take the velocity dependence into account. (However doing so has little impact on current constraints.)
We report the corrected exclusion regions superseding previous limits from XQC, CRESST Surface Run, CMB power spectrum and extensions with Lyman-$α$ and Milky Way satellites, and Milky Way gas clouds. Some limits become weaker than previous bounds in the literature, while others become stronger. Gaps which open by correct treatment of some particular constraint can sometimes be closed using a different constraint. We also discuss the dependence on mediator mass and give approximate expressions for the velocity dependence near a resonance. Sexaquark ($uuddss$) DM with mass around 2 GeV, which exchanges QCD mesons with baryons, remains unconstrained for most of the parameter space of interest.
A statement in the literature that a DM-nucleus cross section larger than $10^{-25}\,{\rm cm}^2$ implies dark matter is composite, is corrected.
CMB Spectral Distortions from Resonant Conversions in Atomic Dark Sectors
C.N. Yang Institute for Theoretical Physics, Stony Brook University（杨振宁理论物理研究所，石溪大学）；Center for Theoretical Physics - A Leinweber Institute, Massachusetts Institute of Technology（麻省理工学院莱因韦伯理论物理中心）；Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology（麻省理工学院卡夫利天体物理学与空间研究研究所）
Rekindling s-Wave Dark Matter Annihilation Below 10GeV with Breit-Wigner Effects
Laboratoire d’Annecy de Physique Théorique, CNRS – USMB（理论物理安纳西实验室，法国国家科学研究中心-萨瓦大学）；Institute for Particle Physics Phenomenology, Department of Physics Durham University（达勒姆大学粒子物理现象学研究所）
Primordial Physics in the Nonlinear Universe: signatures of inflationary resonances, excitations, and scale dependence
University of Chicago（芝加哥大学）；Kavli Institute for Cosmological Physics, University of Chicago（芝加哥大学卡弗里宇宙物理学研究所）；NSF-Simons AI Institute for the Sky (SkAI)（NSF-西蒙斯天空人工智能研究所（SkAI））；University of Pennsylvania（宾夕法尼亚大学）；Center for Particle Cosmology, Department of Physics and Astronomy, University of Pennsylvania（宾夕法尼亚大学物理与天文学系粒子宇宙学中心）
LAPTh, CNRS, USMB（拉普斯理论物理实验室，法国国家科学研究中心，萨瓦大学）；School of Physics and Astronomy, University of Southampton（南安普顿大学物理与天文学学院）；New York University Abu Dhabi（阿布扎比纽约大学）；IPPP, Department of Physics, Durham University（达勒姆大学物理系粒子物理理论与哲学中心）；Laboratoire de Physique de Clermont Auvergne (UMR 6533), CNRS/IN2P3 Univ. Clermont, Auvergne（克莱蒙费朗奥弗涅物理实验室，法国国家科学研究中心/法国国家核物理及粒子物理研究所，克莱蒙奥弗涅大学）；Skobeltsyn Inst. of Nuclear Physics, Moscow State Univ.（莫斯科国立大学斯科别尔钦核物理研究所）
Impostor Among $ν$s: Dark Radiation Masquerading as Self-Interacting Neutrinos
Saha Institute of Nuclear Physics（萨哈核物理研究所）；Homi Bhabha National Institute（霍米·巴巴国立学院）；Washington University（华盛顿大学）；Johannes Gutenberg-Universität Mainz（美因茨约翰内斯古腾堡大学）；Southern University of Science and Technology（南方科技大学）；The University of Texas at Austin（德克萨斯大学奥斯汀分校）
